The
central Italian states under papal sovereignty between 756, when Pepin
the Short presented Ravenna to Pope Stephen II (reigned 752-57), and
1870. They included parts of Emilia-Romagna, Marche, Umbria, and Lazio.
They were a major obstacle to the movement for Italian unification but
were finally annexed in 1870. The popes refused to recognize their loss
of temporal power until the Lateran Treaty (1929) established the Vatican
City as an independent papal state.